Darkness" is a state without light. "Light" is truth from the Lord, so "darkness" represents a state where truth is lacking. Here's a cogent passage from Arcana Coelestia: "The person who has yet to be regenerated is called 'a void and an empty earth', and also 'ground', in which no good or truth at all has been sown - 'void' where there is no good, and 'empty' where there is no truth. Consequently there is 'thick darkness', or stupidity and lack of knowledge about anything that has to do with faith in the Lord and so anything that has to do with spiritual and celestial life. (Arcana Coelestia 17)

3038. 'To your seed I will give this land' means the Divine Truth which belonged to the Lord's Human. This is clear from the meaning of 'seed' as the faith that is an expression of charity, and also those in whom such faith is present, dealt with in 1025, 1447, 1610, 2848 (and since all good and truth of faith are received from the Lord, it is Divine Truth itself that is meant in the highest sense by 'seed'); and from the meaning of 'this land', namely Canaan, as heaven or the Lord's kingdom, dealt with in 1413, 1437, 1607. And as heaven or the Lord's kingdom is meant, it is the Lord's Divine Human itself that 'the land of Canaan' is used to mean in the highest sense. For the Divine itself cannot flow into heaven except through the Lord's Divine Human, which the Lord also made plain in Matthew,

All things have been delivered to Me by My Father; and no one knows the Son except the Father, nor does anyone know the Father except the Son and he to whom the Son wishes to reveal Him. Matthew 11:27.

And in John,

Nobody has ever seen God; the only begotten Son who is in the bosom of the Father, He has made Him known. John 1:18.

'The Son' is the Lord's Divine Human. Anyone who believes that in heaven they worship any other Father than the Lord is much mistaken.